title: Current sunscreen controversies: a critical review.
abstract: OBJECTIVE
  Sunscreens are believed to be a valuable tool in providing photoprotection against the detrimental effects of UV radiation, a known carcinogen. However, a number of controversies have developed regarding their safety and efficacy. This review summarizes the relevant studies surrounding these controversies.
  
  
  METHODS
  Evidence of the prevention of skin cancer, an oft-cited reason for sunscreen use, was examined as it pertains to squamous cell carcinoma, basal cell carcinoma and melanoma. We also reviewed studies examining the effects of sunscreen on the synthesis of vitamin D, an essential nutrient whose role in health and disease continues to grow. Lastly, we analyzed studies surrounding the safety and toxicity of oxybenzone, retinyl palmitate and nanoparticles of zinc oxide (ZnO) and titanium dioxide (TiO2 ).
  
  
  RESULTS
  The overwhelming majority of available data is drawn from studies conducted using antiquated sunscreen formulations. Nonetheless, our research revealed that topical use of sunscreen protects against squamous cell carcinoma, does not cause vitamin D deficiency/insufficiency in practice and has not been demonstrated to adversely affect the health of humans.
  
  
  CONCLUSIONS
  Given the established benefits of UV protection, the use of sunscreens remains an important part of an overall photoprotective strategy. Future sunscreens with improved formulation should ideally offer superior protection. With increased usage of sunscreen by the public, continuous and vigilant monitoring of the overall safety of future products is also needed.
authors.affiliation: Dermatology Service, Memorial Sloan-Kettering Cancer Center, New York, NY 10022, USA.
authors.forename: Mark E
authors.initials: ME
authors.lastname: Burnett
authors.forename: Steven Q
authors.initials: SQ
authors.lastname: Wang
mesh_terms: D000818:Animals; D002280:Basal Cell Carcinoma / Q000517:prevention & control; D002294:Carcinoma, Squamous Cell / Q000517:prevention & control; D006801:Humans; D012878:Skin Neoplasms / Q000517:prevention & control; D013473:Sunscreening Agents; D014808:Vitamin D Deficiency / Q000139:chemically induced
chemical_list: D013473:Sunscreening Agents